code:
    File.open(filename_out, 'w+:UTF-8') do |merge_file|
      File.open(filename_chinese, "r:UTF-8") do |f|
        merge_file.write(f.read)
      end
    end


few lines of input / output
input:
<DIALOG Name="Win_Login" Width="226" Height="423" CanMove="false">
	<Resource>
		<FrameImage FileName="Frame\LoginAccountBg.tga"/>
	</Resource>
	<EDIT Name="DEFAULT_Txt_Account" x="46" y="75" Width="133" Height="18" MaxLen="50" Command="login">
		<Text FontName="方正细黑一简体" FontSize="10" Color="255,255,128,255"/>
	</EDIT>


output:
<DIALOG Name="Win_Login" Width="226" Height="461" CanMove="false">
਍ऀ㰀刀攀猀漀甀爀挀攀㸀ഀഀ
		<FrameImage FileName="Frame\LoginAccountBg_20120925.tga"/>
਍ऀ㰀⼀刀攀猀漀甀爀挀攀㸀ഀഀ
	<EDIT Name="DEFAULT_Txt_Account" x="46" y="101" Width="133" Height="18" MaxLen="50" Command="login">
਍ऀऀ㰀吀攀砀琀 䘀漀渀琀一愀洀攀㴀∀뤀捥왫텾ž聎卻≏ 䘀漀渀琀匀椀稀攀㴀∀㄀　∀ 䌀漀氀漀爀㴀∀㈀㔀㔀Ⰰ㈀㔀㔀Ⰰ㄀㈀㠀Ⰰ㈀㔀㔀∀⼀㸀ഀഀ
	</EDIT>
਍ऀ㰀䔀䐀䤀吀 一愀洀攀㴀∀吀砀琀开倀愀猀猀圀漀爀搀∀ 砀㴀∀㐀㘀∀ 礀㴀∀㄀㔀㜀∀ 圀椀搀琀栀㴀∀㄀㌀㐀∀ 䠀攀椀最栀琀㴀∀㄀㠀∀ 倀愀猀猀眀漀爀搀㴀∀琀爀甀攀∀ 䴀愀砀䰀攀渀㴀∀㈀　∀ 䌀漀洀洀愀渀搀㴀∀氀漀最椀渀∀㸀ഀഀ